天然气/柴油双燃料发动机电控喷气技术研究

本文研制开发了天然气／柴油双燃料发动机的压缩天然气（ＣＮＧ）电控喷气系统。试验表明，电控喷气可以明显改善双燃料发动机的燃料经济性和排放性能，提高发动机的热效率。合理选择加载喷射压力和喷射相位可有效地提高燃烧速度和燃烧稳定性。     

ＬＰＧ／柴油双燃料发动机优化研究

本文采用复燃料供给方式，在单缸直喷式柴油机上进行了ＬＰＧ／柴油双燃料的优化试验研究，对比分析了柴油和双燃料及不同掺烧比下双燃料的燃烧特性，着重研究了分析了双燃料发动机在不同压缩比下的最高燃烧压力、最大压力升高率、压力循环变动及燃烧放热规律，并以此为依据优选了双燃烧发动机的压缩比。试验结果表明，降低压缩比后，双燃料发动机的最高燃烧压力及最大压力升高率均有较大降低，同时压力循环变动变小，但着火延迟期，燃烧持续期都会有所增加。     

液化石油气／柴油双燃料发动机放热规律分析

利用CB366燃烧分析仪测录的液化石油气（LPG）／柴油双燃料发动机和原柴油机示功图，比较了LPG／柴油双燃料发动机和原柴油机的燃烧特性及负荷对二者的影响，分析了供油提前角、掺烧比两因素对最高燃烧压力、燃烧放热率、着火开始时刻等双燃料发动机燃烧特性的影响，得出了有关双燃料发动机燃烧特性的结论。     

车有压缩天然气／柴油双燃料发动机燃料供给系统总体设计研究

通过对压缩天然气（CNG）／柴油机燃料发动机的燃料供给系统总体方案的研究，以及对掺烧CNG策略分析研究，提出了一种双燃料发动机燃料供给系统。     

氨燃料内燃机研究现状及展望

为了满足碳中和目标,除了采用电驱系统和燃料电池发动机,还需要开发零碳或低碳燃料内燃机,以满足不同应用场景需求。氨作为零碳燃料和富氢载体,在碳中和时代越来越受到关注,成为研究热点。在总结氨及氨与其他燃料组成的混合燃料燃烧特性和燃烧机理基础上,分析氨在内燃机上应用的可行性,及与化石燃料内燃机相比氨内燃机显现的新特点,提出未来应用需要解决的关键技术。现有研究表明：氨燃料与其他高活性燃料组合,采用高活性燃料引燃是内燃机上比较可行的技术方案。内燃机可采用汽油、天然气、氢气引燃,与传统汽油机相比,在不改变发动机结构情况下,气态氨使内燃机动力性能降低,同时NOx和未燃NH3排放增加。压燃内燃机可采用低自燃温度燃料如柴油、二甲醚等引燃。与纯柴油或二甲醚内燃机相比,氨内燃机动力性能降低,排放与燃料混合比例相关。在所有引燃燃料中,采用氢燃料引燃燃烧改善效果最大,且为零碳排放,因而氨氢融合内燃机是碳中和时代非常有竞争力的零碳动力。未来,实现氨氢融合燃料内燃机应用也需要解决一些研发课题,包括专用氨喷射系统研发、合适的后处理系统研发和车载氨裂解系统研发等。     

氨燃料发动机研究现状及发展趋势

介绍了氨的理化及燃烧特性,分析了国内外氨燃料发动机的发展历程和研究现状,研究了氨燃料发动机在技术可行性、推广应用基础、节能环保、能源安全等方面的优势,进一步讨论了氨燃料发动机在今后发展中所面临的挑战及应对策略,并指明了氨燃料发动机的发展趋势.     

掺烧比对P50/甲醇双燃料发动机燃烧与排放的影响

燃料富氧重整和双燃料燃烧模式是改善燃烧过程和降低颗粒物排放的重要方法.在一台四缸增压中冷的高压共轨柴油机上,采用进气道喷射甲醇、缸内喷射P50(50％体积比例柴油与50％体积比例PODE)的双燃料模式,研究掺混比对P50/甲醇双燃料发动机燃烧与排放特性的影响.研究结果表明:相比于纯柴油模式,P50及P50/甲醇双燃料燃...     

引燃量与压缩比对甲醇/F-T柴油发动机燃烧特性的影响

为改善双燃料发动机大负荷粗暴燃烧,通过一系列台架试验,研究了费托(Fischer-Tropsch,F-T)柴油比例和发动机压缩比对此燃烧模式的燃烧特性的影响。试验中,采用煤基甲醇和F-T合成油柴油形成的全煤基双燃料发动机,采用高十六烷值的F-T柴油引燃甲醇预混合气。结果表明:与原机相比,双燃料发动机的燃烧更柔和,燃烧持续期明显缩短,经济性随F-T柴油比例增大和压缩比的减小而变差;随F-T柴油比例增加,燃烧粗暴程度增大,但在低F-T柴油比例下,降低压缩比有利于降低燃烧粗暴程度。因此,采用低比例F-T柴油适当减小压缩比有利于改善甲醇/F-T柴油双燃料发动机的燃烧和经济性能。     

CNG/柴油双燃料发动机燃烧特性研究

基于某高压共轨柴油机进行CNG/柴油双燃料发动机的燃烧特性研究。在不同工况下通过改变引燃柴油的喷射参数及空燃比改变燃烧特性,对发动机燃烧压力进行实时测量,对比分析双燃料发动机与柴油机的燃烧差异及引燃油量、引燃时刻和空燃比对双燃料发动机燃烧的影响。基于试验得出双燃料发动机的放热率、起燃时刻及燃烧持续期等特征,从而给出双燃料发动机性能提升建议。     

LPG／柴油双燃料发动机应用特性研究

本文采用复合燃料供给方式，在ＺＨ１１０５Ｗ型柴油机上进行了ＬＰＧ／柴油以燃料的应用研究试验，评价了ＬＰＧ／柴油双燃料发动机的动力性、经济性、排放等性能。试验结果表明：与燃纯柴油相比，双燃料发动机的动力性稍差，但经济性好，碳烟排放低。     

基于传统动力源的重型商用车减碳技术

在全球能源危机和温室效应加剧的大环境下，中国向世界承诺减碳目标：2030年前力争实现碳达峰，2060年前力争实现碳中和。作为节能减排的重点，重型商用车的减碳成效是“双碳”征程中的关键。重点介绍基于传统动力源的重型商用车减碳技术，包括内燃机燃烧、低摩擦、智能变速、轻量化、混合动力等技术在内的动力总成领域，以及包括天然气、含氧燃料、氢氨燃料在内的先进燃料领域。通过不同领域的技术发展以及优势互补，更加高效、低碳、清洁的内燃机仍将在重型商用车领域持续发挥重要作用。     

Reduction of emissions with propane addition to a diesel engine

Recent studies on dual-fuel combustion in compression-ignition (CI) engines, also known as diesel engines, fall into two categories. In the first category are studies focused on the addition of small amounts of gaseous fuel to CI engines. In these studies, gaseous fuel is regarded as a secondary fuel and diesel fuel is regarded as the main fuel for combustion. The objectives of these studies typically involve reducing particulate matter (PM) emissions by using gaseous fuel as a partial substitution for diesel fuel. However, the addition of gaseous fuel raises the combustion temperature, which increases emissions of nitrogen oxides (NO_x). In the second category are studies focused on reactivity-controlled compression-ignition (RCCI) combustion. RCCI combustion can be implemented by early diesel injection with a large amount of low-reactivity fuel such as gasoline or gaseous fuel. Although RCCI combustion promises lower NO_x and PM emissions and higher thermal efficiency than conventional diesel combustion, it requires a higher intake pressure (usually more than 1.7 bars) to maintain a lean fuel mixture. Therefore, in this study, practical applications of dual-fuel combustion with a low air-fuel ratio (AFR), which implies a low intake pressure, were systemically evaluated using propane in a diesel engine. The characteristics of dualfuel combustion for high and low AFRs were first evaluated. The proportion of propane used for four different operating conditions was then increased to decrease emissions and to identify the optimal condition for dual-fuel combustion. Although the four operating conditions differ, the AFR was maintained at 20 (? approximately equal to 0.72) and the 50% mass fraction burned (MFB 50) was also fixed. The results show that dual-fuel combustion can reduce NO_x and PM emissions in comparison to conventional diesel combustion.     

Exhaust emissions and its control methods in compression ignition engines: A review

Extensive usage of automobiles has certain disadvantages and one of them is its negative effect on environment. Carbon dioxide (CO₂), carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NO_x), sulphur dioxide (SO₂) and particulate matter (PM) come out as harmful products during incomplete combustion from internal combustion (IC) engines. As these substances affect human health, regulatory bodies impose increasingly stringent restrictions on the level of emissions coming out from IC engines. This trend suggests the urgent need for the investigation of all aspects relevant to emissions. It is required to modify existing engine technologies and to develop a better after-treatment system to achieve the upcoming emission norms. Diesel engines are generally preferred over gasoline engines due to their undisputed benefit of fuel economy and higher torque output. However, diesel engines produce higher emissions, particularly NO_x and PM. Aftertreatment systems are costly and occupy more space, hence, in-cylinder solutions are preferred in reducing emissions. Exhaust gas recirculation (EGR) technology has been utilized previously to reduce NO_x. Though it is quite successful for small engines, problem persists with large bore engines and with high rate of EGR. EGR helps in reducing NO_x, but increases particulate emissions and fuel consumption. Many in-cylinder solutions such as lower compression ratios, modified injection characteristics, improved air intake system etc. are required along with EGR to accomplish the future emission norms. Modern combustion techniques such as low temperature combustion (LTC), homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI) etc. would be helpful for reducing the exhaust emissions and improving the engine performance. However, controlling of autoignition timing and achieving wider operating range are the major challenges with these techniques. A comprehensive review of diesel engine performance and emission characteristics is given in this paper.     

Combustion phase detection algorithm for four-cylinder controlled autoignition engines using in-cylinder pressure information

For several decades, the primary goal of the automotive industry has been to reduce harmful emissions and improve fuel economy. Gasoline engines are clean and powerful propulsion systems, but have poorer fuel economy than that of diesel engines. However, due to the development of new technologies such as variable valve timing and lift and direct gasoline injection, controlled autoignition (CAI) combustion can be realized. CAI engines combine the advantages of cleaner emissions and lower fuel consumption than conventional spark-ignition gasoline engines. In this study, a cylinder-pressure-based combustion phase detection method for CAI combustion is proposed. This method utilizes a normalized difference pressure (NDP), which is defined as the normalized pressure difference between the firing and motoring in-cylinder pressures. The proposed method was developed and validated with steady-state experimental data from an inline 4 cylinder, 2 L gasoline direct injection (GDI) CAI engine. Because the calculations in the NDP method are faster and simpler than in the conventional combustion phase detection method in CAI engines, this method can be embedded in a real-time controller. Furthermore, the proposed method displayed good accuracy in detecting the combustion phase and thus stabilized CAI combustion. Finally, the detailed experimental results are presented.     

Exhaust nanoparticle emissions from internal combustion engines: A review

This paper reviews the particle emissions formed during the combustion process in spark ignition and diesel engine. Proposed legislation in Europe and California will impose a particle number requirement for GDI (gasoline direct injection) vehicles and will introduce the Euro 6 and LEV-III emission standards. More careful optimization for reducing particulate emission on engine hardware, fuel system, and control strategy to reduce particulate emissions will be required during cold start and warm-up phases. Because The diesel combustion inherently produces significant amounts of PM as a result of incomplete combustion around individual fuel droplets in the combustion zone, much attention has been paid to reducing particle emissions through electronic engine control, high pressure injection systems, combustion chamber design, and exhaust after-treatment technologies. In this paper, recent research and development trends to reduce the particle emissions from internal combustion engines are summarized, with a focus on PMP activity in EU, CARB and SAE papers and including both state-of-the-art light-duty vehicles and heavy-duty engines.     

Applicability of heat transfer equations to hydrogen combustion

Previous research by the authors showed that hydrogen combustion exhibits a higher cooling loss to the combustion chamber wall of an internal combustion engine compared to hydrocarbon combustion because of its higher burning velocity and shorter quenching distance. The high cooling loss means that reduction of the cooling loss is essential to establish a high thermal efficiency in hydrogen combustion engines. This research analyzed the applicability of equations to describe the heat transfer from burning gases to hydrogen combustion. The result shows that equations calculate a lower cooling loss than experimental values, and the use of correction coefficients does not accurately define the actual cooling rate. It is therefore concluded that the derivation of a new heat transfer equation for hydrogen combustion is necessary to improve the thermal efficiency of hydrogen fuelled engines.     

稀燃汽油机NOx净化技术--吸附还原催化法试验研究

简述了降低稀燃汽油机NOx排放的催化分解法、选择还原催化法和吸附还原催化法。在8A-FE型汽油机上进行的试验表明，吸附还原催化法可有效地降低稀燃汽油机的NOx排放。建议采用传统三效催化器在前、稀燃NOx吸附还原催化转化器在后的联合布置方案，并严格限制汽油中的含硫量。     

掺氢比对氢-甲醇发动机稀薄燃烧及排放影响

为探究掺氢比对氢-甲醇发动机稀薄燃烧性能的影响，在一台1.8 L涡轮增压缸内直喷汽油机 （GDI） 改装的氢-甲醇发动机上，开展了不同燃空当量比和不同掺氢比条件下的甲醇发动机掺氢燃烧和排放试验研究。结果表明，在稀燃条件下，增大掺氢比能提高发动机缸内最高燃烧压力及放热率峰值，且燃烧相位提前，燃烧持续期缩短。在稀燃情况下适当掺氢有助于改善循环变动，混合气越稀改善效果越好，但随燃空比和掺氢量增大时，循环变动却有恶化的趋势。当燃空当量比大于 0.71 时，增大掺氢比能改善 HC 排放；当燃空当量比大于 0.83 时，掺氢能改善 NOx排放，但 CO 排放恶化；当燃空当量比小于0.83时，增大掺氢比导致NOx排放恶化但CO排放降低。     

新型代用燃料天然气合成油的研究进展

综述了天然气合成油(GTL)作为柴油机代用燃料在燃料生产,雾化和燃烧,有害排放,燃料性质,环境潜力和经济成本等方面研究的国际进展;介绍了GTL能同时降低有害排放的试验研究情况;指出了GTL发动机研究目前存在的问题和今后的研究方向;最后分析了我国发展GTL的意义、途径和条件。     

车用直喷式柴油机排气净化的途径

在改善车用柴油机燃油经济性的同时，需进一步降低氮氧化物和微粒排放，关键是进一步优化燃烧过程，减少有害排放物的生成，也要改善燃料品质，甚至进一步采用排气后处理技术，本文阐述了喷油系统和进气系统的改进，燃烧室设计的优化，增压中冷，废气再循环等技术措施的潜力，以及燃油改质，排气后处理等措施的效果。